This invention relates generally to methods and apparatus for preparing artificial dentures, and more particularly concerns a method of preparing false teeth and associated structure which will feel comfortable to the user, appear inconspicuous and natural to the observer, and yet which can be offered to the patient at low cost.
Traditionally, methods of preparing complete or half sets of dentures have been complex, time consuming, and consequently expensive for the patient. These methods, in general, include the following steps:
1. Primary impressions of the patient's mouth are taken with an appropriate impression material.
2. After these impressions are poured in dental stone or plaster, the casts are used to construct custom trays.
3. Final impressions are taken using these custom trays filled with a paste or rubber impression material to obtain a more accurate stone cast of those portions of the patient's mouth which are proximate to or will coact in some way with the artificial dentition to be provided.
4. These final stone casts are fitted with heat molded base plates and wax biterims.
5. The biterims are tried in the patient's mouth and carefully adjusted to proper occlusal plane, length, and lip support. The midline is marked and upper and lower biterims are fixed in the proper centric relations by means of a paste or softened wax.
6. Teeth elements are selected for proper size, shape and shade.
7. The base plate-and-biterim assemblies are fixed in an articulator by means of dental stone or plaster.
8. The artificial teeth elements are individually set into the wax biterims. Each individual tooth is set in softened wax in proper relationship to adjacent teeth, the patient's lips, and into the proper occlusion.
9. Space surrounding the teeth is filled with wax, and the wax is carefully carved to simulate gum tissue.
10. The tooth, biterim and base plate assemblies are now tried into the patient's mouth and are evaluated for proper aesthetics and bite relations. In most cases, this tryin proves unsatisfactory.
11. Corrections are made to each assembly, and further tryins are made until proper fit, bite relation and aesthetics are obtained.
12. A molding post dam is placed into the upper model to compensate for shrinkage of the base material. Both wax set ups are luted with wax to the stone cast. Final carving of the tissue areas is completed.
13. The model portion of the wax denture is invested with plaster in a split metal flask. After the plaster is set and painted with separating medium, the top portion of the flask is filled with dental stone or plaster, and that material is allowed to harden.
14. The flasks are placed in hot water to soften the wax, and the wax is flushed out.
15. A separating medium is painted upon all plaster or stone surfaces, and is allowed to dry.
16. Acrylic, vinyl or other material suitable for denture base use is mixed and packed into the mold.
17. The mold flasks are closed, and clamped in the closed position.
18. The mold flasks are now immersed in water. Both the water and the immersed flasks are then heated gradually to set the denture material.
19. The hot flasks are permitted to cool slowly, the flasks are opened, and the dentures are removed and cleansed of plaster.
20. The dentures are remounted on the articulator to again grind the teeth into proper occlusion. This occlusial reorientation is necessary because of small but noticable distortions of the heat-cured denture base materials.
21. The dentures are now separated from their models, and all remaining stone and plaster is removed with rotary instruments and sandpaper.
22. After final polishing and cleaning, the dentures are delivered to the patient.
From this description, it will be apparent that the present method of constructing dentures is an extremely complicated, time-consuming and expensive undertaking. So expensive, indeed, is this method that many elderly persons living on modest incomes are unable to afford dentures. As a result, many such persons are, quite simply, left without teeth.
It is accordingly the general object of the present invention to provide a relatively inexpensive, quick, and less complex method of preparing dentures.
A more specific object of the invention is to provide a method of preparing dentures which makes effective use of pre-formed tooth and gum tissue elements.
Another object is to provide a method and associated apparatus for preparing artificial dentures which results in a denture end product of attractive, natural appearance and close, comfortable fit for the user.
Other objects and advantages of the invention will become apparent upon reading the following detailed description and upon reference to the drawings. Throughout the drawings, like reference numerals refer to like parts.